CN101203686A - Lubricating device for rolling bearing - Google Patents

Abstract

A lubricating device for a rolling bearing having a function of cooling an inner ring, which reduces stirring resistance of cooling oil accompanying high-speed rotation of the rolling bearing. A cooling oil introduction member (11) provided with a nozzle (12) for discharging cooling oil to a circumferential groove (6) on the end surface of an inner ring (2) is disposed on the back side of an angular ball bearing (1), a seal section (13) facing a tapered surface (2b) holding gap is formed by an extension section (11a) of the cooling oil introduction member (11), and the gap (6) of the seal section (13) is set to 0.2mm or less, whereby the inflow amount of cooling oil flowing from the seal section (13) into the bearing can be suppressed to a small amount, and the stirring resistance of the cooling oil accompanying the high-speed rotation of the angular ball bearing (1) can be reduced.

Description

Lubrication device for rolling bearings

technical field

The present invention relates to a lubrication device for a rolling bearing having a cooling function for an inner ring.

Background technique

In a rolling bearing that supports a rotating shaft that rotates at high speed, such as a main shaft of a machine tool, the temperature of the inner ring is higher than that of the outer ring due to machining loads or the like. Therefore, the preload of the bearing becomes too large due to the thermal expansion difference between the inner ring and the outer ring due to the temperature difference, and there is a problem that the life of the bearing is shortened.

To solve this problem, there is a lubricating device for rolling bearings, which sprays cooling oil supplied from a cooling oil supply device from one end in the axial direction of the rolling bearing to the inner ring of the rotating ring, and is provided with the inner ring from which the cooling oil is sprayed. The outer diameter surface on one end side of the bearing maintains a gap facing the sealing part, so that part of the cooling oil flows into the bearing from the gap of the sealing part as lubricating oil, and does not install other cooling devices and also has the cooling function of the inner ring (for example, Refer to Patent Document 1).

Patent Document 1: Japanese Unexamined Patent Publication No. 2004-360828 (Figs. 5-7)

In the lubrication device for a rolling bearing described in Patent Document 1, when the gap between the outer diameter surface of the inner ring and the seal portion increases, the amount of cooling oil that flows into the bearing as lubricating oil increases. However, in a rolling bearing that supports a rotating shaft that rotates at a high speed of 10,000 revolutions per minute or more, such as the main shaft of a machine tool, when the amount of cooling oil flowing into the bearing increases, cooling will be brought along with the high-speed rotation of the rolling bearing. The stirring resistance of the oil increases, so there is a problem that the power loss increases.

Contents of the invention

An object of the present invention is to provide a lubrication device for a rolling bearing that also has a cooling function for an inner ring, and to reduce the agitation resistance of cooling oil accompanying the high-speed rotation of the rolling bearing.

In order to solve the above-mentioned problems, the present invention provides a lubricating device for rolling bearings, which adopts the structure that the cooling oil supplied from the cooling oil supply device is sprayed from one axial end side of the rolling bearing to the inner ring of the rotating ring, and is provided with the lubricating device. The outer diameter surface on the one end side of the inner ring from which the cooling oil is sprayed maintains a gap facing the sealing portion, and a part of the cooling oil sprayed to the one end side of the inner ring is used as lubricating oil from the outer diameter surface of the inner ring. The lubricating device of the rolling bearing is characterized in that the gap between the outer diameter surface of the inner ring and the sealing part is set to be 0.2 mm or less.

The present inventors varied the gap δ between the outer diameter surface of the inner ring and the seal portion in various ways, and measured the inflow amount Q of cooling oil flowing from the gap δ into the inside of the bearing. As a result, as shown in FIG. 4 below, the inflow amount Q of the cooling oil tends to become a horizontal line because the amount is small when the gap δ is 0.2 mm or less, and increases sharply when the gap exceeds 0.2 mm. According to the measurement results, by setting the gap between the outer diameter surface of the inner ring and the seal part at 0.2 mm or less, the inflow of cooling oil into the bearing can be stably suppressed to a small amount, thereby reducing the amount of cooling oil that is accompanied by high-speed rolling bearings. The stirring resistance of the cooling oil brought by the rotation.

In addition, the present invention provides a lubricating device for a rolling bearing, which adopts the structure that the cooling oil supplied from the cooling oil supply device is sprayed from one axial end side of the rolling bearing to the inner ring of the rotating ring, and is arranged to be connected with the sprayed oil. The outer diameter surface of one end side of the inner ring of the cooling oil maintains a gap facing the sealing part, and a part of the cooling oil sprayed to the one end side of the inner ring is used as lubricating oil from the outer diameter surface of the inner ring and the sealing part. The gap in the bearing flows into the inside of the bearing. The lubricating device for the rolling bearing is characterized in that an oil groove extending in the circumferential direction is provided on the inner diameter surface of the sealing part facing the outer diameter surface of the inner ring.

That is, by providing an oil groove extending in the circumferential direction on the inner diameter surface of the seal portion facing the outer diameter surface of the inner ring, the sealing performance is improved, and the inflow of cooling oil into the bearing is stably suppressed at A small amount can reduce the stirring resistance of the cooling oil brought by the high-speed rotation of the rolling bearing.

Invention effect

In the rolling bearing lubricating device of the present invention, part of the cooling oil flows into the bearing as lubricating oil, and the gap between the outer diameter surface of the inner ring and the seal part is set at 0.2mm or less, so the cooling oil flowing into the bearing can be The amount of inflow is stably suppressed in a small amount, which can reduce the stirring resistance of the cooling oil brought about by the high-speed rotation of the rolling bearing.

In addition, the lubricating device of the rolling bearing of the present invention also adopts a structure in which an oil groove extending in the circumferential direction is provided on the inner diameter surface of the sealing part facing the outer diameter surface of the inner ring, so that the sealing performance is good, so that the oil flowing into the bearing The amount of inflow of cooling oil is stably suppressed to a small amount, thereby reducing the agitation resistance of the cooling oil accompanying the high-speed rotation of the rolling bearing.

Description of drawings

Fig. 1 is a structural view showing a main shaft device and a cooling oil supply device connected thereto of a rolling bearing lubrication device according to the present invention;

Fig. 2 is an enlarged cross-sectional view showing part A of the lubricating device of Fig. 1;

Fig. 3 is an enlarged cross-sectional view showing part B of the lubricating device of Fig. 1;

4 is a graph showing the results of measuring the relationship between the gap δ of the seal portion and the inflow amount Q of cooling oil flowing into the bearing.

Symbol Description

1. Angular contact ball bearings

2. Inner ring

3. Outer ring

2a, 3a, orbital surface

2b. Tapered surface

3b, taper hole

4. Ball

5. Retainer

6. Circumferential groove

11. Cooling oil introduction components

11a. Extension

11b. Lead-in hole

11c, discharge hole

11d, discharge groove

11e, connecting hole

12. Nozzle

13. Sealing part

14a, 14b, oil storage space

15. Cover member

16. Oil tank

20. Spindle

21. Bearing box

21a. Inner box

21b. Outer box

22. Inner ring spacer

23. Inner ring pressure ring

24. Outer ring spacer

25. Outer ring pressing ring

30. Cooling oil supply device

31. Cooling oil circulation circuit

32. Supply path

32a. Branch supply path

33. Return path

34a. Lead-in hole

34b, discharge hole

35. Pressure regulating valve

36. Oil filter

37. Lead-in hole

38. Oil recovery circuit

39. Oil pump

40a, 40b, discharge holes

Detailed ways

Embodiments of the present invention will be described below based on the drawings. FIG. 1 shows a main shaft device of a machine tool to which the lubricating device for rolling bearings according to the present invention is applied. The spindle device is equipped with a chuck of a tool or a workpiece at the end, and the spindle 20 driven by a motor (not shown in the figure) is driven by two rolling bearings, namely angular contact ball bearings 1, which are separately installed in the axial direction on the bearing box 21. support. In addition, as will be described later, a cooling oil supply device 30 for supplying cooling oil for cooling the bearing housing 21 and the inner ring 2 of the angular contact ball bearing 1 is connected to the spindle device.

As shown in Fig. 2, in the above-mentioned angular contact ball bearing 1, the balls 4 are held by the cage 5 between the raceways 2a and 3a of the inner ring 2 and the outer ring 3, and the inner ring 2 is loaded with axial load on the front side. On the inner diameter surface of the outer ring 3, a taper hole 3b is provided, and on the outer diameter surface of the inner ring 2 on the back side, a tapered surface 2b that expands toward the raceway surface 2a is provided, and a tapered surface 2b is provided on the end surface in the circumferential direction. Extended circumferential groove 6.

As shown in Figure 1, the above-mentioned bearing housing 21 is a two-layer structure composed of an inner box 21a and an outer box 21b, and the inner rings 2 of the two angular contact ball bearings 1 are provided with an inner ring spacer 22 and are externally embedded on the main shaft 20 , and both sides are fixed with the inner ring press ring 23. In addition, the two outer rings 3 with the outer ring spacer 24 provided therebetween contact the cooling oil introduction member 11 constituting the lubricating device of the present invention with the end face on the back side, and are fitted in the inner case 21a to press the rings with the outer rings. 25 fix its both sides.

A cooling oil circulation path 31 is formed between the inner case 21a and the outer case 21b of the above-mentioned bearing housing 21, and the cooling oil circulated and supplied from the cooling oil supply device 30 through the supply path 32 and the return path 33 passes on the outer diameter surface of the outer case 21b. The provided inlet hole 34 a and outlet hole 34 b are supplied to the cooling oil circulation path 31 .

In addition, a branch supply path 32a interposed with a pressure regulating valve 35 and an oil filter 36 is provided in the supply path 32 of the cooling oil supply device 30, and the cooling oil is supplied to each introduction hole 37 provided on both ends of the inner case 21a. The cooling oil supplied to each introduction hole 37 is guided to the cooling oil introduction member 11, and is used for lubricating the inside of the bearing of each angular contact ball bearing 1 and cooling the inner ring 2 as described later, and then recovered to the inner case 21a. The oil recovery path 38 provided on the lower side returns to the cooling oil supply device 30 through the oil pump 39 .

As shown in FIG. 2 , the cooling oil introduction member 11 abutting against the back side end surface of the outer ring 3 is embedded in the inner case 21 a, and is provided with an introduction hole 11 b communicating with the introduction hole 37 of the inner case 21 a, and its The tip is provided with a nozzle 12 for spraying cooling oil to the circumferential groove 6 of the inner ring 2 . In addition, on the front side of the cooling oil introduction member 11, there is provided an extending portion 11a forming a sealing portion 13 extending between the inner ring 2 and the retainer 5 and facing the tapered surface 2b of the inner ring 2 to maintain a gap δ. The protruding portion 11 a forms an oil storage space 14 a around the circumferential groove 6 . Most of the cooling oil that has been sprayed into the circumferential groove 6 and cooled the inner ring 2 is stored in the oil storage space 14a, and is sealed from the communication hole 11e provided in the cooling oil introduction member 11 to the cover member 15 mounted on the rear side thereof. The oil storage space 14b moves.

Part of the cooling oil that has been sprayed toward the above-mentioned circumferential groove 6 and cooled the inner ring 2 is guided to the gap of the seal portion 13 along the tapered surface 2 b by the centrifugal force generated with the rotation of the inner ring 2 , and flows from the seal portion 13 as lubricating oil. to the inside of the bearing. In order to suppress the inflow of cooling oil into the bearing to a small amount, the gap δ between the tapered outer surface 2b of the inner ring 2 and the inner diameter surface of the protruding portion 11a at the sealing portion 13 is set to 0.2 mm. In addition, two oil grooves 16 extending in the circumferential direction are provided on the inner diameter surface of the protruding portion 11a, so that the sealing performance is improved, and the inflow of cooling oil into the bearing is stably suppressed to a small amount.

As shown in FIG. 3 , the cooling oil introduction member 11 is provided with a discharge hole 11 c communicating with the oil storage space 14 b and a discharge groove 11 d communicating with the inside of the bearing along the end surface of the outer ring 3 . Moreover, the discharge hole 40a, 40b which connects these discharge hole 11c and 11 d of discharge grooves with the oil recovery path 38 is provided in the lower part of the inner case 21a, respectively. Therefore, the cooling oil that cools the inner ring 2 and is stored in each oil storage space 14b is recovered to the oil recovery path 38 through the discharge holes 11c and 40a, and part of the cooling oil lubricated inside the bearing passes through the discharge groove 11d and the discharge holes 40b and The bearing back side oil drain hole 40c is recovered to the oil recovery path 38 .

Example

The gap δ of the sealing portion 13 as shown in FIG. 2 was changed, and the inflow amount Q of the cooling oil sprayed from the nozzle 12 into the inside of the bearing from the sealing portion 13 as lubricating oil was measured. The diameter of the main shaft 20 (inner diameter of the angular contact ball bearing 1 ) was set to 70 mm, the rotational speed thereof was set to 30000 rpm, and the discharge rate of the cooling oil from the nozzle 12 was set to 0.6 liter/minute.

FIG. 4 shows the measurement results of the inflow amount Q of the above-mentioned cooling oil. From the measurement results, it can be seen that the inflow amount Q of the cooling oil tends to become a horizontal line because the amount is small when the gap is 0.2 mm or less, and it increases rapidly when the gap exceeds 0.2 mm. Therefore, by setting the gap δ of the seal part to 0.2mm or less, the inflow quantity Q of the cooling oil flowing into the bearing can be stably controlled to a small amount, thereby reducing the stirring resistance of the cooling oil caused by the high-speed rotation of the bearing. .

In addition, in terms of the temperature rise of the inner ring cooled by cooling oil, even if the bearing is rotated at a high speed of 55,000rpm at the highest level, the bearing is about 60°C, and its radial expansion is about 0.09mm. Therefore, when using such a high-speed rotation In the case of rolling bearings, if the gap δ is set to a value close to the upper limit of 0.2 mm, a gap for allowing part of the cooling oil to flow into the bearing as lubricating oil can be secured.

In the above embodiments, the rolling bearing is an angular contact ball bearing, however, the rolling bearing lubrication device of the present invention can also be applied to other rolling bearings such as deep groove ball bearings and roller bearings.

Claims (2)

1. A lubricating device for a rolling bearing, which sprays cooling oil supplied from a cooling oil supply device from one end in the axial direction of the rolling bearing to the inner ring of the rotating ring, and is provided with one end of the inner ring from which the cooling oil is sprayed. The outer diameter surface of the side maintains a gap facing the sealing part, so that part of the cooling oil sprayed to one end side of the inner ring flows into the bearing as lubricating oil from the gap between the outer diameter surface of the inner ring and the sealing part, so that The lubricating device of the rolling bearing is characterized in that, A gap between the outer diameter surface of the inner ring and the seal portion is set to be 0.2 mm or less. 2. A lubricating device for a rolling bearing, which sprays the cooling oil supplied from the cooling oil supply device from one axial end of the rolling bearing to the inner ring of the rotating ring, and is provided with one end of the inner ring from which the cooling oil is sprayed. The outer diameter surface of the side maintains a gap facing the sealing part, so that part of the cooling oil sprayed to one end side of the inner ring flows into the bearing as lubricating oil from the gap between the outer diameter surface of the inner ring and the sealing part, so that The lubricating device of the rolling bearing is characterized in that, An oil groove extending in the circumferential direction is provided on an inner diameter surface of the seal portion facing the outer diameter surface of the inner ring.

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